1. Field of the Invention
This invention relates to organic polymeric peroxides containing ester groups in the molecules which can be used as free radical polymerization initiators for vinyl-type monomers.
2. Description of the Prior Art
Polymeric diacyl peroxides which are obtained by reacting dibasic acid chlorides with sodium peroxide are known.
For example, H. V. Pechman et. al. report in Bericht Der Deuchen Chemichen Gesselshaft 27, 1510 (1894) that polymeric diacyl peroxides are obtained from phthalic acid chloride and sodium peroxide.
N. A. Milas et. al. disclose in J. Amer. Chem. Soc. 68, 534 (1946) that oxalic acid chloride is reacted with sodium peroxide, thereby obtaining the corresponding polymeric diacyl peroxide.
Further, N. S. Tsvetkov et. al. report in Chem. Abst. 60, 5293d (1964) and ibid 60, 10892e (1964) that aliphatic dibasic acid chlorides are reacted with sodium peroxide whereby some kinds of polymeric diacyl peroxides having the following formula are obtained: ##STR1## WHEREIN N IS 2-10 AND X IS 16-35.
It has been known that the above-mentioned polymeric diacyl peroxides are useful as polymerization initiators for vinyl monomers.
For example, N. S. Tsvetkov et.al. disclose in Chemical Abstracts 67, 54,445a (1967) that when these peroxides are used as the polymerization initiator, the molecular weight of the thus-obtained polymer was twice that of the polymer produced when benzoyl peroxide was used.
A. Ya. Sorkin et.al. disclose in Chemical Abstracts 84, 136120f (1976) that when these peroxides were used as the polymerization initiator for vinyl acetate, the resultant polymers had larger molecular weights and fewer branches in the molecule, in comparison with that obtained by using benzoyl peroxide.
Sugimura et.al. report in Japan Technical Chemistry 69, 718 (1966) that styrene-methyl methacrylate graft-polymer was obtained by using poly(phthaloyl peroxide).
As described in the foregoing, a polymeric diacyl peroxide is a useful polymerization initiator but it has the following defects:
(1) It is an explosive compound which is sensitive to impact, friction and heat. (refer to Chemical Abstracts 59, 7651a (1963)).
(2) It cannot be used as an industrial polymerization initiator, since its solubility in an organic solvent and vinyl-type monomers is low. (refers to Japan Industrial Chemistry 69, 718 (1966) and Chem. Abst. 64, 15989g (1966).